Method of carbonizing coal.



H. L. DQHERTY.

METHOD OF CARBONIZING COAL. APPLICATION HLED MAR.21,1913- RENEWED MAR. 11.1916.

1 1 97,804; Patented Sept. 12, 1916.

4 SHEETS-SHEET 1.

V I I witnesses: fi W vwan w'b H. L. DOHERTY.

METHOD OF CARBONIZING COAL. APPLICATION FILED mm. 21. I913- RENEWED mm. H. IBIS.

Patented Sept. 12, 1916.

4 SHEETS-MEET 2- FIGZ H. i. DOHERYY. METHOD OF CARBOMZING COAL. APPLICATION FILED MAR. 21,1913. RENEWED MAR, Ii. 191s.

. PatentedSept. 12, 1916.

H. L. DOHERTY.

METHOD OF CARBONIZING COAL. APPLICATION FILED mm. 2!. ma. RENEWED mm. H. l9i6.

1 1 97,804. Patented Sept. 12, 1916.

4 SHEETS-SHEET 4.

,UNITED STATES PATENT OFFICE.

HENRY L. DOHER'XY, 01? ThlEW YC'RK, N.

Application filed March 21, 1913. Serial No.

To all whom it 111 (13/ (OTUWH Be it known that I, llnunr L. Donrnrry, a Citizen of the l mited States. and a resident of New York dry, in the county of New York and State of New York, have invented certain new and useful lrnprovm ments in Methods oi (:nbonhing Coal, of which the following a speoifimuiirm.

This invention relates to methods of can bonizing coal and similar materials, and, in particular, to a method of continuous carbonization in shaft furnaces.

The objects of my invention are to supply to the art a eontiniuius method of carbonizing fuel that will enable the oar mnization to be carried out holly, or in great part, by the heat developml by the earbonizing reactions themselves, ell'eet the automatie gasifieation in the Ctlibullillllg apparatus of p rzuttioally all of the heavier tar produuts. so that the will be taken oil of the can bonizer praotioally free from all heavy pitch-forming constituents, and lamp black, and will permit of the witluirawal of the gas and coke from the oarbonizer practically cold. i

To this-end, my invention. briefly state-(l, comprises the carrying out of the rarbonizw tion in a emnparatively high shaft having a coal preheating and gas cooling section, a earbonizing sertion proper, a heat generating sertion. and a cooling section for the rarbonized fuel. by rim-.ulating through the rharge a suitable heatarrying medium, the said heat-earrying medium being first passed in eontart with the hot carbonized fuel in the lower part of the shaft, thence in ('ontact with superheated coke or other carbonized fuel in a mid portion of the shaft, them-o in contact. with the material to be carbonized in the upper part of the shaft, whereby the said material is subjeoted to grmlual heating to the temperature of oarbonization while the circulating medium and the gas generated cooled to beagain introduced, in part, into the bottom of the shaft for the completion of another cycle. The superheating of the coke or carbonized material is performed by maintaina cross-draft of superheated air at the superheating section to heat the material to in candescenee with the production of pro- Snea-ifieatson of Letters Patent.

either intermittentlyor continuously.

755,955. Renewed March 11, 1916. Serial No. 88,676.

ducer gas which burned to heat the air for the (-,ross-(lr:ilT.

I am aware that t ha litn propoi-aw'l be [ore to Parry out tza' rarhonhcation of coal in shaft turn-ares by eirtulatingr gase us fluids. but all of those lurve suffered from the deter that the exljrzine uis l t. w ich it i:-; nec inedhun owing to various losses, had to be supplied by transni' ion of heat to the gaseous lluizl by eoinluetion from exteriorlyheated walls.

One inrentmproposrto return a portion f the gas drawn oil of the top of the (au'bonizer to the base of the a 'qimratus and pass the same u 'iward thr-iuigh the hot can bonined roal to cool he some and to heat the returned gins. lue healed gas hen passes in contact with the, coal in the upper portion of the shaft giving up heat to the same and effecting its oarbonization. The heat losses are supplied by stopping the gas making operation during the drawing of the carbonized material and ten'iporarily op erating the earbonizinq shaft a gas pro duoer by introducing air at the bottom and permitting it to asee d through the hot coke or other carbonized material. The result is the generation of produrer gas which is burned in an annular jacket snrrouiiding the earbonizing shaft pauper, the heat so generated passing through the. wall into the. coal undergoing carbonization. he in- Yentor also describes a modification of the above method in which he blasts a separate fuel bed to incandeseenoe and carries the heat of the same into the carbonizing shaft by passing the, cold returned gas through the said separate fuel bed and thence into the coal undergoing carlmnization, instead of through the (arrbonized material.

Another method known to the art, per-- forms the earbonization of the eoal by heat ing a portion of the gas made in an teriorly tired fur-nave, and then passing it downward through the partially preheated coal to be carbonized: In this case the preheating is also performed by external heat ing oi the shaft walls, while the cooling of the varbonizol material is performed, wholly, by external cooling of the walls of the lower portion of the shaft. This method is sill more objectionable than the sary to supply to tlio eu'euluti'ogi' of heat, either to or from the shaft walls.

y my invention, on the other hand, I do away, entirely, with the necessity for the transmission of heat to or from the charge in the shaft through the shaft Walls. All

heating and cooling is done by directly contaeting with the material a suitable fluid at a suitable temperature. The extreme distance to which the heat must be transmitted by conduction depends simply upon the size of the fragments of the charge and is measured by the shortest distance from the center of the largest fragment to the surface of the same. The heat required to institute the carbonizing action and to supply any necessary extraneous heat to the same is communicated to the carbonized material in the shaft itself by blasting the same with highly superheated air to form producer gas, which is burned to perform the superheating of the air.

The blasting of the coke or other carbonized material leaves it in a liighly incandescent state. The circulating gaseous fluid, which has been used to quench the carbonized material in the lower part of the shaft and has thus itself been heated nearly or quite to the proper carbonizing temperature, is next passed in contact with the incandescent coke, to become superheated to the proper degree, and hence passes in contact with the material undergoing carbonization. By my invention there is, thus, no interference with the cooling of the coke during the period of extraneous heating of the material undergoingmrbonization. The coke, which is subjected to the superheating, is that portion of the charge in the shaft which has just been carbonized and which is still at the maximum carbonizing telnperature. There is no interference with the regular operation of the carbonizer and the operation of storing up heat in the coke to be transferred to the carbonizing charge may be carried out continuously without interrupting the carbonizing operation. Besides the ones enumerated. my invention comprises other features of increased utility which will be made plain below.

In the accompan vin, drawings l have shown an apparatus embodiment of my invention adapted to advantageously carry out the process features of the same.

Figure 1 is a vertical diamctrical section through the shaft and its appurtenant regencrators on the linc l--l of Fig. 2. Fig. 2 is a horizontal section through the same at the level 2-2 of Fig. 1. Fig. 3 is a plan of the apparatus with the operating floor removed. Fig. -t a partial front elevation of the same from the position indicated by .ing through elongated valve the line H of Fig. 3. Fig. 5 is a vertical section similar in position to Fig. 1 through a modified form of apparatus in which the superheating of the coke may be carried out continuously without interrupting the normal carbonizing operation.

In the drawings 1 indicates the carbonizing furnace or shaft, as a whole; 2 designates the fuel preheating section; 3 the carbonizing section proper; 4 the coke superheating section; and. 5 designates the coke cooling section of the shaft.

It is to be understood that there is no sharp line of demarcation between the several sections of the shaft, but that the several regions, designated for convenience of reference by the several numerals mentioned, blend one into the other. The limits of the regions in which the several operations enumerated take place is largely a matter of the temperature existing at the different levels. The upper border of the coke superheating section (numbered 4) is more or less sharply defined by the level of the upper ports 28 in the apparatus of Fig. l; but this is the only approximately fixed boundary plane separating the several sections.

6 and 6' are the regenerators.

7 is a blower for supplying air for blasting the coke during the superheating of the same. 8 is the discharge conduit of the blower 7, having branches 9 and 9 conducting air to the lower parts of regenerators 6 and 6', respectively. A bypass 10, having a valve 32, serves to conduct a portion of the heated air from the upper part of one regenerator to the upper part of the other. Valves l2 and 12' on 5 and 9', respectively, serve to divert the flow of air from one con duit to the other, according to the direction of the blow through the carbonizer. These valves are usually arranged to be operated from the operating floor by means of operating gears 13 and 13'. respectively, actstems l-l and 14, respectively, which latter have on their upper ends racks which engage, respectively, with gears 13 and 1 1'. 15 is another blower, preferably of the positive type. which serves to circulate the gas or other heat-carrying medium through the charge in the shaft. 7

16 and 16 are condensers or scrnbbers 16 for the portion of the circulating gas which is returned to the carbonizcr and the other, 16, for the treatment of the gas going to the usual purifiers (not shown). In 16 the returned gas is, preferably, scrubbed with a portion of the tar oils (or some equivalent liquid which will absorb the illnminants from the The gas returns to thc carbonizer, therefore, comparatively free from those hydrocarbons which would be dissociated by repassing through the hot coke.

22 is the gas oft-take leading from the transferred to superheating section 4. This is a decided advantage, inasmuch as much less air is required to produce a given temperature increment in the carbonized mate- .rial in 4, and the duration of the blasting period of blow is greatly shortened both on account of the less volume of air required and the greater pressure (and hence velocity). under which it is supplied. \Vith a low blast pressure, on the other hand, the proportion of CO in the effluent gases is increased and a larger proportion of the total air used'is required in regenerator 6. Inasmuch, however, as the CO produced in 4 is utilized to heat the air for the subsequent blow in the reverse direction, the actual quantity of air required to be passed through the superheating chamber 4 is not increased in the ratio that would otherwise .be indicated by the lower ratio of CO to CO.

. Owing to the relatively low percentage of heat utilization in the regenerators as compared with that in the superheating chamber, however, it is usually desirable to'use the blast under comparatii'ely high pressure (20 to inches of water).

:The distribution of air between 4 and 6' having been properly adjusted by the manipulation of the valve 32, the combustibleconstituents of the gas entering regenerator (3 will be completely burned in the checker of the regenerator, the combustion gases giving up the greater part of their heat to the same, if the capacity of the regenerators has been properly adjusted to the duty required of them. The comparativeiy cool combustion gases discharge from the lower'part of theregenerator through the conduit 30 and pass to the'chinmey 3i.

When'the proper temperature has been attained in the carbonizingchamber, the switch controlling motor 7. is opened, stopping the'blower 7, and valve 12 shut. Valves 26 and 27, are again opened and motor 15 started. Gas again passes up through cooler 5, super-heating section 4. where it is more or less superheated, and thcnce through the coal (or other material) undergoing carthis temperature, of course, nearly all of the 'vapors produced in' the carbonization are condensed, and scrubbed but of the gas I the coal in the preheating chamber 2. T? gas thus leaves the carbonlzer In a fair pure condition carrying, for the most ponly such impurities as are permanent gases (so called) together with a small amount of hydrocarbons of low boiling point and water vapor. These latter are condensed in the condensers 1G and 16, leaving the gas clean and in admirable condition to undergo the ordinary purification treatment.

The condensation of tarry matter in the coal in preheating chamber 2, if permitted to proceed uninterrupted, would eventually impede the flow of the gases and clog the operation of the carbonizer. To correct this tendency I, at intervals, change the direction of the run, passing the circulating gaseous stream downward through the material undergoing carbonization. This is effected by closing valves 26 and 27 Queennections 22 and 25 and opening valves 33 and 3i on connections 35 and 36, respectively. The blower 15 now forces the gas, which it draws from the condenser and scrubber 16, through conduits 25 and 36 to the upper part of fuel-preheating chamber 2 of shaft 1, thence down through the shaft and through conduit 35,. to condensers 1(5 and 16. In passing down through the interstices of the charge, the gas carries downward the accumulated tarry matter into the hottest region of the shaft in the superheating section 4. In contact with the hot coke, the tar-forming compounds are broken up to form permanent gases, difficultly-condensible hydrocarbons and free carbon. The returned gas, together with the new gas generated, passes down through the shaft in contactwith the previously cooled coke in the cooler 5, giving up most of its sensible heat to the same, and thence passes to the condensers, as before described. Since the apparatus is so designed and operated that'in normal working there will always be a considerable body of cold coke in chamber 5, and since the duration of the down blow is comparatively brief, the relatively high temperature region in the shaft will not be carried downward to an extent 'that'will interfere with the working upon returning to the normal up-runs. This method of securing the gasification of matter condensed in the upper part of the fuel column, by reversing the normal direction of the run, I do not claim specifically herein, that forming a specific feature of the invention disclosed in my application Ser. No. 660,450, referred to above. This element is only claimed herein in connection with other elements of the specific process disclored.

When the temperature in the superheating chamber i has again fallen below that required for proper carbonization, the blower 15 is again shutdown, the valves on the gas connections on the shaft 1 closed, blower 7 started, valve 12 opened and valve 32 is adjusted to give the proper distribution of the air between (5' and 4. Air now termittent.

9 to the lower part of regfcnerator (3. passes up through the previously heated checkerwork in the same, thence through the nostrils in into the snperheating chamber -l. tlSSlllQ through the coke, in l, combustion is again instituted w th the f rmation ofinore or tiblc gas. and the reheating of the coke. The clli tllt gas passes through the nostrils 21: into the regenerator h. Then it minglcs with the air flowing to (3 through the bypasslll and burns. The combustion gases pass down through the checker 557 in (3' giv ing up most of their heat to the same, thence flow through conduit ill) (valve 22 being open) to the chimney 31. If desired, a boiler for generating steam, or other heat utilizing apparatus may be interposed between the stack andthe rcgenerators.

The relative duration of the runs ilows through and blows will vary with the character of the.

coal used, the cross dimension of the stack and various other considerations. The larger the cross section of the stack the less is the 'adiating surface compared with the quantity of material under treatment and consequently the less is the percentage heat loss. \Vith a comparatively large cross section of the stack, with some coals, the car bonizer having once been put in normal operating condition, the carbonization may be sustained indefinitely without having recourse to blasting to recoup heat losses. \Yith other fuels, more or less frequent blasting may be required to maintain the temperature at the proper point for carbonization. \Vorking with apparatus of comparatively small cross section and with a gas coal of only average quality l have found that four minutes blasting to thirty minutes of run willamply sutiice to maintain the temperature of the carbonizer.

PllG'IHOVQIllQDi} of the charge through the carbonizcr may be either continuous or in- As fast as the relatively cold coke. is removed at the. bottom of the shaft, coal is, of course, charged in at the top, so that the charge in the shaft is always main tained at substantially the same level.

\Vith most coals it is advantageous to feed with the coal a certain proportion of coke, after the method disclosed by me in apl'ilications. Ser. Nos. (360,450; 30,451, tit'ithlflil, and 370,338. The object of admixing preforn'icd coke with the coal charged is to prevent the. formation of large coke aggregates which would oll'er obstruction to the passage of the blast, forcing the draft urrent to the walls and thus interfere with the uniform distribution of the draft throughout the. body of the charge. This latter r quirement is of special importance in the practice of my invention in that depend upon the direct contact between the circulating heat'carrying medium and the less combus 't'ragments of the charge for the transfer of heat from one portion of the charge to the other.

\Yhen deemed desirable, steam may be used in admixture with the returned gas, or even used alone as the heat-carryingniedium. \l'hen the carbonization is carried on at a omparatively high temperature, above lHll) degrees ll. the presence of steam in the gas returned, of course, involves a proportionate combustion of coke to form water gas. When (airying on the :arbonization at a relatively low temperature, say 1000 de grees to 1200 l steam alone may be the heat-carrying medium with used as out the formation of any great amount of water gas. In this case, it is, of course, necessary to so operate the apparatus that the coke and gas will both be withdrawn at temperature above 212" F. The Steam withdrawn may be separated from the gas by condensation. it has been determined by experiment that coal may be practically completely carbonized at a temperature as low as eoo degrees F., when the time of treatment is sutliciently prolonged. When carbonized at this temperature, while the make of gas is low, the candle power per ton of coal and the value of the condensation products are high. With apparatus in common use, however, it is ditiicult to maintain the necessary uniform low temperature throughout the charge. 'lherefore, carbonization at low temperatures has been but little used. My invention, however, peculiarly well suited to carrying out the low temperature distillation of coal. In cases where the coal is sutliciently exothermic in its carbonization, and where the apparatus is properly designed, after the carbonization has once. been properly established, it may be maintained indefinitely at tttlllll'llh tures as low as 900 degrees to 1000 degrees l By means of thc'apparatus embodinu-ntof my invention shown in Fig. 5. the blasting of the coke may be carried out without any interruption of the. make of gas. in this, the chamber in which the coke is blastcd is not traversed by the circulating gaseous heat-carrying medium.

The method of operation is as follows: The coal is, as before, preheated in a preheating chamber 2, carbonized in a lower portion 3 of the shaft 1, blasted in a mid section t, and quenched and cooled in cooler 71 in the lower portion of the shaft. The circulating gas. however, is withdrawn from the shaft traversing before the superhiaiting chamber 4, through the line it), by the fans 41. and reintroduced again into the shaft. through the conduit 42 above the. chamber l. in this type of apparatus l. preferably, al though not necessarily, us a rcgencral r of the double surface type, commonly called liltl recuperators in the art. 'In this type the 'air flows through the fines 43, of the recuperator 44, to the super-heating chamber 4, through the coke occupying this chamber, burning more or less of the latter to form producer gas and to heat the coke. Under the induction exerted by the chimney 45, the producer gas flows into and through the conduit 46. thence through the fines 47 of the recuperator 44. Air is admitted to the flues 47 through the dampers 48, burning the combustible constituents of the producer gas. The heat generated is to a large extent transmitted through the flue walls to the inflowing air passing through the'flues 43. The air thus reaches the super-heating chamber 4 at a high temperature and but little combustion is necessary to impart a suitable temperature to the coke. The spent combustion gases from the tiues 47 How to the chimney 45, which supplies the inductive effect necessary to draw in the air through the dampers 48. As coke is withdrawn at the bottom of the shaft, the heated coke in 4 descends into the upper-part of the cooler 5 and. is thus brought into contact with the ascending stream of circulating gas.

The operation of this modification of my invention is, in other respects than the ones just described, essentially the same as in the case of the first form of apparatus.

I claim:

1. The process of carbonizing fuel and producing which comprises advamring a body of ma? *rial containing the fuel to be carbonized downwardly through a relatively long conduit, maintaining a carbonizing temperature at a mid-region in said conduit by burning a portion of the carbonized fuel in said mid-region by passing laterally therethrough a combustion supporting draft current, withdrawing cool distillation gas from the upper part of said conduit, diverting a portion of the distillation gas, passing the sald diverted gas upwardly through the hot carbonized fuel advancing from said mid-region, thence in contact with the hot carbonizing fuel in said mid-region, thence through the material in the upper portion of said conduit in admixture with the distillation gases from said carbonizing region.

2. The process of carbonizing fuel and producing gas which omprises advancing a body of material containing the fuel to be carbonized downwardly through a relatively long conduit, maintaining a carbonizing temperature at a mid-region in said conduit by burning a portion of the carbonized fuel in said region by passing laterally therethrough a combustion supporting draft current, cooling the carbonized materlal that has advanced beyond said mid-region by passing upwardly therethrough a current of initially cool gaseous fluid, passing said the lower portion of gaseous fluid through the hot carbonized material in said mid-region thence through the material above said mid-region, Where y said material above said region is subjected to a carbonizing temperature and the material in the up 1' portion of said material above said region is subjected to preheating, while the said gaseous fluid and the distillation gases from the carbonized material are cooled, and withdrawing the cooled gases from the upper part of said conduit.

3. The process of carbonizing fuel and producing gas which comprises advancing a body of material containing the fuel to be carbonized dowmvardly through a relatively long conduit. maintaining a carbonizing temperature at a mid-region in said conduit by burning a portion of the carbonized fuel in said region by intermittently passing laterally therethrough a combustion supporting draft current, cooling the carbonized material that has advanced beyond said midregion by passing upwardly therethrough a current of initially coo gaseous fluid, passing said gaseous fluid through the hot carbonized material in said mid-region, thence through the portion of the material above said mid-region whereby the lower part of the said portion of material is subjected to carlmnization while the upper part of said portion of the material is subjected to preheating. while the said gaseous fluid and the distillation gases produced in the carbonization of said material are cooled, and witlnlrawing'the cooled gases from the upper part of said "iduit.

l. The process 0. carlsmizing fuel and producingdistillation gases which comprises advancing a body of material containin the fuel downwardly through a relativelyfiong conduit, maintainin r a carbonizing temperature at a. mid-region in said conduit by passing laterally through carbonized material in said mid-region a stream of preheated air, cooling the carbonized material that has advanced beyond said mid-region by passing upwardly therethrough a current of initially cool gaseous fluid, passing said gaseous fluid through the hot carbonized material in said mid-region, thence through thematerial above said mid region, whereby the lower portion of the said said mid-region is subjected to -a carbonizingtemperature and the upper portion of said material is subjected to preheating, while the said gaseous fluid and the distillation gases from the carbonized material are cooled. and withdrawing the cooled gases from the upper part of said conduit.

5. The process of carbonizing fuel and producing distillation gases which comprises advancing a body of material containing the fuel downwardly through a relatively long conduit, maintaining a carbonizing temperatnre at a mid-region in said conduit by intermittently passing laterally through carbonized material in said mid-region a stream upwardly through the carbonized material through the material in the part of saidcon duit above said mid-region, whereby. the

lower portion of said material is subjected to carbonization and the upper portion of said material is preheated. while the said gaseous fluid and the distillation gases from the carbonization of said fuel are cooled, and withdrawing the cooled gases from the upper part of said conduit.

(i. The process of carbonizing fuel and producing distillation gases which comprises advancing a body of material containing the fuel downwardly through a relatively long conduit, maintaining a carbonizing temperature at a mid-region of said conduit by intermittently passing laterally through carbonized material in said mid-region, first "in one direction and then in the reverse direction, a current of preheated air to produce combustible gas and to heat said carbonized fuel, witlulrawing the so-prmluccd com-bustible gas from said conduit and' burning the same to heat air for the reverse blast. passing upwardly throughthc carbonized material below said mid-region a current of'initially cool gaseous lluid, whereby the said carbonized nla terial is cooled and the said gaseous fluid heated. passing the so-hcated gaseous fluid through the heated carbonized material in *tact withthe heated carbonized material In said mid-region to further heat said gaseous lluid, thence through the material in the paltof said conduit above said midrcgion whereby the lower portion of said material is subjected to carbonization and the upper portion of said material is heated, while the said gaseous lluid and the distillation gases from the carbonization of said fuel are cooled, and \vitlnlrawing the cooled gases from the upper part of said conduit.

T. The process of carbouizing fuel and producing distillation gases which comprises advancing a body of nnltel'ial containing the fuel do\\'nw:mlly, through a relatively long conduit, maintaining a carbonizing tcm aa'ature at a mid-region of said conduit by intcrmittcntly blowing laterally through carbonized material in said luida'egion, lirst in one direction and then in the reverse direction a current of preheated air to produce combustible gas and to heat said carbonized fuel, withdrawing the combustible gas formed during the blow in one direction and burning said gas to heat air to be used in the blow in the reverse direction, withdrawing distillation gas from the upper part of said conduit, diverting a portion of the distillation gas withdrawn, introducing said diverted gas into the lower part of said conduit and passing the said gas upwardly in contact with the carbonized material discharged from the said midregion to preheat said gas and to cool said carbonized material, passing the preheated gas in Contact with the heated carbonized material in said inidregion to further heat said gas, and passing said gas through the material above said mid-region to carbonize the lower portion of said material and to preheat the upper portion of said material.

8. The process of carbonizing fuel and producing distillation gases which comprises advancing a body initially composed of fresh fuel and carbonized material downwardly through a relatively long conduit, maintaining a carbonizing temperature at a mid-region of said conduit by intermittently blowing laterally through carbonized material in said mid region, first in one direction and then in the reverse direction a current of preheated airto produce combustible gas and to heat said carbonized fuel, withdrawing the. combustible gas formed during theblow in one direction and burning said gas to heat air to be used in the blow in the reverse direction. withdrawing distillation gas from the upper part of said conduit, diverting a portion of the dis tillation gas withdrawn, introducing said diverted gas into the lower part of said conduit and passing the said gas upwardly in contact with the carlmnized material dis- Lcharged from the said mid-region to preheat said gas and to cool said carbonized ma terial, passing the preheated gas in-conisaid mid-region to further heat said gas, passing said gas through that portion ofsaid fuel mixture above said mid-region to carbonize the fuel in the lower part of said .of initially cool bonizd fuel in said mid-region by passing laterally therethrough a combustion supporting draft current, withdrawing cool distillation gasfrom the upper part of said conduit, diverting a portion of the distillation gas, passing the said diverted gas upwardly through the hot carbonized fueladvancing beyond said mid-region, thence in contact with the hot carbonizing fuel in said mid-region, thence through the material in the upper portion of said conduit in admixture with the distillation gases from said carbonizing region, withdrawing cool: carbonized fuel from the bottom of said has advanced beyond said niid region by passing upwardly therethrougli a current gaseous fluid, passing said gaseous fluid through the hot carbonized material in said mid-region, thence through the portion of the material- ,above said midregion, whereby thelower part of said portion of said material is subjected to a carbonizing temperature and the .material inv the upper part of said portion of said material is subjected to preheating, while the said gaseous fluid introduced and the distillation gases from the carbonized ,material are cooled, withdrawing the cooled gases from said conduit, withdrawing cool carbonized material from said conduit, admixly composed of'freslrfuel and ing a portion of the carbonized material. withdrawn with fresh fuel and feeding sa d mixture on to the top of said fuel body.

11. The process of carbonizing fuel and producing gas which comprises advancing a body of material containing the fuel to be carbonized downwardly through a relatively long conduit, maintaining a carbonizing temperature at a mid-region in said conduit by burning a portion of the carbonized fuel in said mid-region by passing laterally therethrougha combustion supporting draft-cu1 rent, normally withdrawing cool distillation gas from the upper part of said conduit,divex-ting portion of the distillation gas, passing the said diverted gas upwardly through the hot carbonized fuel advancing from said mid-region, thence in contact with the h t carbonizing fuel in said mid-region, thence through the material in theiupper portion of said conduit in admixture,.with the distillation gases'from said carbonizing sous fluid by pasisng the same during normal region, and periodically reversing the direction of flow of said diverted distillation gases, said diverted gases passing during reversal first in contact with the raw fuel, thence into and throughthe hot carbonized fuel in said mid-region, whereby tarry matter condensed in said raw fuel is carried down into contact with said hot carbonized fuel and gasified, withdrawing the gases formed from a locality below said mid-region, diverting a portion of said diverted gases'and returning said diverted gases to the upper part of said fuel body.

12. The process of carbonizing fuel and producing gas which comprises advancing a body ofmaterial containing the fuel to be carbonized downwardly through a relatively long conduit, maintaining a carbonizing temperature at a mid-region in said conduit by burning a portion of the carbonized fuel in said region by passing laterally therethrough a combustion supporting draft current, normally cooling the carbonized-material that has advanced beyond said midregion by passing upwardly therethrough a current of initially cool gaseous fluid, thence passing said gaseous fluid through the hot carbonized material in said mid-region, thence through the material above said midregion, whereby the lower portion of said material is subjected to a carbonizing temperature, the upper portion of said material to preheatin and tarry constituentscondensed out of said gaseous fluid, periodically reversing the direction of flow of said gasefirst through the upper portionj of said fuel body above said mid-region, thence downwardly through the hot carbonized fuel in said mid-region, whereby said condensed tarry constituents are gasified, withdrawing'cool distillation gas from the upper portion of said fuel body flow of said gaseous fluid and from the lower part of said fuel body dur-- ing reversal.

13. The process of carbonizing fueland producing gas which comprises advancing a body of material containing the fuel to be carbonized downwardly through a relatively long cgnduit, maintaining a carbonizing temperature at a mid-region in said conduit by burning a portion of the carbonized fuel in said region by intermittently passing laterally therethrough a combustion supporting draft current, normallvcooling the carbonized material that has lvanced be; yond said mid-region by passing upwardly therethrmigh a current of initially cool gaseous fluid; thence passing said gaseous fluid through the hot carbonized material in said mid-region, thence through the portion of the material above said mid-region, whereby the lower part of said portionof the material'is subjected to cai'honization, the upper part of said portion of the material 7 I, I while the said gaseous fluid 'md the distillation gases produced in the ll uzation of said material are cooled irry liquid condensed therefrom, perire ersing the direction of flow of gaseou v fluid oy passing the same first fifllll lftlfloll, thence through the hot loci in said mid-region, where- Ml condensed tarry liquid is gasified, El mtlulrarwing cool distillation gases the upper portion of said fuel body as: {normal flow of said gaseous fiuid rom the lower portion of said fuel during reversal. Thr process of carbonizing fuel and dstillation gases which comadnnring a body of material inironiposed of fresh fuel and carbon- 1 "l in admixture downwarlilly through el long conduit, maintaining a cartemperature at a mida'egion in by burning a portion of the w l url in said u1id-region by passlrra l thcrethroug'h a combustion ,iim; draft current, normally withi ii}; (will distillation gas from the upper l, ,d mid conduit, diverting a portion d1 tillation gas, normally passing Ell iver-led gas upwardly through ll hot carbonized fuel advancing in contact slit) x i on? mid-region, thence l the portion of said fuel body above with the hot carbonized fuel in said 1nidregion, thence through the portion of said body of material above said 1uid-region to carbonize fresh fuel, thence in admixture with the distillation gases from the carbon ized fresh fuel through the upper portion of said body of material to preheat said material, to cool said gases and to condense tarry liquid from said gases, periodically reversing the flow of said distillation gases, Withdrawing cool distillation gases from the lower part of said fuel body, diverting a portion of said distillation gases, passing said diverted portion of said distillation gases downwardly through the mixture of fresh and carbonized fuel in the upper portion of said fuel body, thence through the hot carbonized fuel in said mid-region, whereby said condensed tarry liquid is gasified, withdrawing cool carbonized fuel from the bottom of said conduit, admixing a portion of said carbonized material with fresh fuel and introducing the said mixture into the upper part of said conduit.

Signed at New York city, in the county of New York and State of Jew York, this 17th day of Man, A. D. 1913.

HENRY L. DOHERTY.

Witnesses:

WILLIAM 0. Dustin, Tnos. I. CARTER. 

